It doesn't matter which evolution it is. They will receive evs all the same. If they're not increasing with respect to the ev training that you're doing, then it must have 510 evs. I would clear ev'd from the irrelevant stats. (spa, spdef, etc)

For ingame purposes, you don't really need flawless or even good natured stuff. :P

Honestly. I've beat the game (HGSS) with a Quiet Typhlosion, a Quiet Starmie, a Timid Scyther, an Adamant Kangaskhan (the only good natured one in the team), a Naughty Quagsire and a Relaxed Hustle Togekiss.